With the growth of the aged population in recent years, the number of patients suffering from pollakiuria or urinary incontinence is increasing. At present, as therapeutic agents for pollakiuria or urinary incontinence, agents having anticholinergic activities and/or muscle relaxant activities are mainly used. However, administration of these therapeutic agents are associated with side effects, for example, dry mouth; gastrointestinal system symptoms such as constipation; cardiovascular symptoms such as orthostatic hypotension; or urinary dysfunction such as urinary retention and residual urine, so that they may not be able necessarily to be administered up to the dose in which their effectiveness is shown. For improvement of quality of life (QOL) of patients, development of a therapeutic or prophylactic agent for pollakiuria or urinary incontinence with less those side effects is strongly demanded.
At present, as therapeutic or prophylactic agents for pollakiuria or urinary incontinence with less possibility of occurrence of dry mouth which is the major side effect of the existing drugs, β3 agonists have been researched and developed. However, it has been suggested that in human, a certain type of β3 agonists shows effects on cardiovascular system such as increase in heart rate and increase in cardiac output, and has a positive chronotropic effect on the heart (Br. J. Clin. Pharmac. 37, 363, 1994). For a therapeutic agent for pollakiuria or urinary incontinence, effects on cardiovascular system are side effects, and in cases where they are severe, they may be factors due to which therapy is stopped, so that a therapeutic agent for pollakiuria or urinary incontinence, from which effects on cardiovascular system are separated to the greatest extent possible, is demanded.
In Japanese Translated PCT Patent Application Laid-open No. 2002-512639, a compound useful for therapy of pollakiuria as a β3 agonist is disclosed, and more particularly, the phenethylamine derivative 1 is disclosed as a therapeutic agent for urinary dysfunction:

However, this prior art reference does not suggest at all that the compound herein, whose structural requirements are different from those of the compound included in the prior art reference, has an anti-pollakiuria activity at a dose at which there is only a very small possibility of occurrence of side effects on cardiovascular system (especially, the heart rate-increasing effect and hypotensive effect), and that the compound is especially useful as a therapeutic or prophylactic agent for pollakiuria or urinary incontinence.
On the other hand, in Bioorg. Med. Chem. Lett., 2001, 11, 3035, the benzylamine derivative 2, which is structurally similar to the compounds herein, and its affinity, selectivity and agonistic activity to β3 receptor are disclosed:

However, its effects as a therapeutic or prophylactic agent for pollakiuria or urinary incontinence, and side effects on cardiovascular system are not disclosed at all.
In U.S. Pat. No. 3,341,584 B, a wide range of compounds including a part of the compounds herein are disclosed. However, the literature is totally silent about effects of these compounds as therapeutic or prophylactic agents for pollakiuria or urinary incontinence. Further, in the literature, compounds having a benzylamine structure characteristic to the compounds herein are not concretely described.
Thus, it could be helpful to provide a novel compound useful as an excellent therapeutic or prophylactic agent for pollakiuria or urinary incontinence with only a very small possibility of occurrence of side effects on cardiovascular system, a pharmaceutical comprising the compound, and a therapeutic or prophylactic agent comprising the compound for pollakiuria or urinary incontinence.